so, should we now look at AP ammo and the way it will work.
its harder job, as, it doesnt open the skin/structure to reveal as easily its damage capability. so, we need cut through pictures of plane. And on that, make some magic bullet theories.
Here is car door, which took really many hits from calibers up to .50cal. If its hinge would be ok, you could still put it on car.
Though it would not look nice, at all.
there is around 200 holes on that door, someone care to count? and if someone would, make also count from different cals, little ones and big ones. you can see it from the size of hole, except from those points which took really many shots at exact same area, eating bigger hole in it. someone earlier asked to shot effect on REAL target by those AP hits. Here is steel "sheet", a car door. You can bet, that every round also penetrated the rear side sheet, easily. I bet Smaller rounds penetrating that door lost some 10-40% of their total kinetic energy. (im not talking about muzzle velocity energy, but the energy they had left when they met that door.
.50 cals most propably didnt lose that much. Thats an assumption. I could claim here,that the rounds could only penetrate only 1 door, and after that they would be useless, just because i dont see behind it, and that there is no witness plate behind it and all that. Would i do it? no.
Here is just for comparison, also a car door, hit with 20mm on its side. 2 shots, one hit the window and other.. (yes its modern ammo, impact detonating HE-I)
how i know its impact detonatin? because steel around the hole is bend away from shooter towars that witness plate behind it( which has dents from fuze parts of those ammunition. thickness of that rear plate is unknown as is hardness.)
care to think/count how many AP hits it would take for them to eat similar size of hole?
i did :) about 700 shots from 7,62mm and 260 12,7 hits.
here is same door, before it gets hit with 20mm HEI. coming from left, notice the door handle on both pics.
as well, upper spar where that door is hanging, is welded behind those 2 other ones standing tall, on both pictures as well.
still hard to believe in impact fuse and direction of fire?
shot hits and explodes right away. some incendiary is going to other side of door, but HE detonates on this side of the door, thus bending the edges away from explosion cause of pressure (= its like really really strong wind blowing for a really brief time.)
I am intrested if anyone got pictures of penetrations from WW2 era AP rounds, no matter if its light mg ammo, or .50cal ammo or 20mm cannon ammo.
Its known, that those weapons can penetrate steel plate from 8mm thick to closer 30mm thick with AP round, dont know about 20mm cannon exact values, as there were different cannons with every nation, and each had different charasterics in ammo velocity, ammo weight, rate of fire..
But with weight and speed one can calculate somewhat accuratelly the penetration capability of each cannons round on single plate.
It is known, that every single penetration through something affects the projectile. It affects its velocity, trajectory, stability=making it unstable and perhaps weight as well. All depending what it hits and at what angle, how heavy projectile is and how fast, its shape etc. And how many times it penetrates something, every time it does so, above mentioned effects increases.
Its a fact, that if you keep caliber and velocity of ammo, but double its weight, its penetration is doubled.
and when you keep same caliber, ammo weight but double its velocity, the penetration is 4 times as much.(and accuracy at long ranges increases because of flatter trajectory, if ammo isnt light comparing to its size. Heavier material can sustain its speed longer time, as will tracer element in its back(reduces drag effect somewhat). also shape has big factor in this.
(best shape for keeping ammunition speed i know (without assistance)is that in the picture below, developed in late 1800´s by swiss professor Hebler.
the shape and air passage reduces air and material resistance huge amounts. Iron made 5mm bullet of such shape was able to penetrate stack of wood(pine) some 204 cm.
(i believe hunting rifles around .308cal are able to penetrate wood some 40-80cm these days.)
it was using kind of sabot behind it to keep gunpowder created pressure behind it, thus forcing it at speeds 1220m/sec
similar 8mm bullet was able to fly 4402 m, and it took 9,16 seconds to get there. It still had velocity at that range some 337m/sec and penetration against wood 27,8 cm. Calculated max range was 8101 m. Pretty good for "AP" ammo of 8mm, at 1890.. thats before over 20 years before WW 1.
(Perhaps adding flechette style thin wings on its tail section would help it keep its course? :P)
back to track.
So, AP ammo penetration capability against harder surfaces is also affected by angle which projectile hits the thing, like armor plate.
If you shoot at armor plate at 30 degree angle(above picture show 45degree, so 15 degree more angle) it means that projectile has to penetrate twice as much material to make it through. At surface side of plate, plate resist the penetration because material gives in more on the surface side than inside the plate, cos surface side there is room for material to move at, but inside the plate, there is no room. It goes opposite way, when projectile starts to penetrate and comes closer the inner side of the plate, then there is again room for material to move away from path of projectile. so, as above picture shows, 45 deg hit, it it penetrates, it would first turn the projectile more upwards, but when its close to other side, its nose would turn downwards(level), cos material gives in on that side.
to clarify that what i mean, again short vid which shows how upper part of simulated aluminium plate over the projectile move over(right wording?) and that guides the projectile back upwards. its just because over the projectile is less resistance for material to move.
there were different kinds of ammuniton used to prevent that ricochet from happening, at least some degree.
here is schematic picture of 109. everyone can see the different parts inside that plane. Most of the WW2 planes have quite the same equipment inside of them, just in different numbers, sizes and places, with some different values as well. Now example is 109.
imagine that you are shooting it directly from behind with 6x .50 cals, at convergence range(which is the meeting point of projectiles, spot where guns are aligned to meet each others fire. the Deadly zone. The burst hits right in the left wing (the wing closer to you, under the fuselage) in the middle of it. it would not take too long to make it Fold/snap under stress while turning and if its not turning(not stressed that much), it would demand little more hits on it then to make it happen. I bet everyone agrees that .50cal bullets would quite certainly go throu entire wing, from rear to front part.
Most of the rounds just need to penetrate 4 layers of aluminium. Im not sure if the main spar is made from steel, might be. Someone can bring that information to light. (too tired to dig it up now)
Some of the bullets might hit the cables running inside the wing, and most likely also cut them, depending how it hits that cable.
Some wing ribs might also be holed up with long cuts, because fire is coming paraller to them.
also rear part of the wing skin would have longer cuts on it, because rounds are hitting it at high angle. from front of the wing, angle isnt that bad, and the holes would not be that big, IF bullets would come out at clean stable trajectory, and wihtout bullets broken in parts. But they have torn in parts, or are flying sideways because skin penetration and penetrations after that, forcing them to lose some of their stability. Some of them come out clean, some comes out sideways, and some in pieces. Most of them lost nose part of their copper jacket, as those had incendiary stuff in their nose, making copper jacket deform/rippin off.(i assume some of them had that in their nose due the flashes in vids, which tells that they are sensitive to impact pressure, causing that stuff to "detonate", which is seen as flash. Some part of that incendiary goes inside the wing, but there is nothing to burn except tire which is rubber. it would exhaust quite Soon™™, as it isnt too willing to burn on itself, after incendiary burns itself up. Tire would be tho "flat", not in flight but when landing, as it needs mass over it to deform that rubber shape it is cast into, when it loses pressurized air from inside of it.
Plane could do it without it. Undecarriage though would be damaged even more if it would land without air in tire.
Rim(?) would also be punctured by bullets and landing would do more damage to it.
Quite many planes have wing as thick as 109 wing, on fighters. clear exception from that is Hurricane, which wing is 30cm(1 feet) thick.
Any fighter plane would last almost as long as 109 wing under .50cal barrage at convergence range. just depending on its thicknes, IF rounds are able to penetrate whole wing.
Exceptions are those, which have more wing spars than one- Two would perhaps mean, that even if both are damaged, it would still be able to withstand more stress/hits, because the fact that there is 2 of them holding the wing in its position, thus sharing the forces. 3 spars is even better, as forces are perhaps divided evenly. that perhaps might not be true, as it might be possible, that depending on spar position, it matters alot.
as, if you remove 2 spars from the forward part of the wing, it might not withstand, but would turn like elevator wing and then rip off.
AP rounds compared to HE rounds are able to tunnel in the plane, deep. able to make hole in several internal strenghtening parts. But same applies locally with cannon HE shells, as well at longer distances with thei fragments, though fragments arent possessing the kinetic energy what 7.62/.50cal/20mm AP rounds have at close/medium ranges. at close range they got enought to put holes in aluminium structures/skin. Mine ammo shells have really poor fragment effect because thin shell and size of fragments it created, except fuse which will get speed Boost from detonation in additition to its velocity when it hit the target. Same applies to fragments but not as much. (10-20% difference)
AP bullet, depending on caliber, is able to travel from tail to fuel tank without much problem, depending on how many inside structures/equipment it hits on its path. HE ammo cannot do that.
HE stop at surface or just under it and damages it and surrounding stuctrures, plus make holes at frontal sector of its fllight path with fragments, depending how fast it was when it hit. it it is standing still fragments would fly from side of grenade to sides of it etc, base part would fly away from it at its rear direction, fuze would go at its nose direction. frontal part of the sides, which is angled, would take forward directions.
AP round penetrating tail can hit oxygen cylinders behind pilot, making them explode. I dont know how much pressure there is, if they are full, the force is up to that and also that how much it is spend. if the pressure is low, it doesnt do anything. But if is pure oxygen and not air, it will certainly boost fire if there is such and cylinder has leaked its oxygen inside the fuselage. Though, holes in the skin would also mean, that there is ventilation effect inside, effectivenes of it is up to speed plane travels, as well altitude it has, as well amount of hole area in its hull, as well where the hole or holes are. if there is 1 at frontal part and second at rear part, it works better than a single hole, i assume.
This also is bad thing, if fuel tank is hit, it could make fire burn inside the fuselage at high heat because of continuous airflow, making it kinda blowtorch, depeds how much air gets inside front of fuel tank/leak position. I think that way it would be more effective. But if air is spent inside the fuselage, fire would burn ouside of it, where is air/oxygen for making it possible. Temperature(high) weakens the structure.
killing pilot thru the rear armor of 109 is quite hard if not impossible from directly behind, because of few reasons. first is that upper part of it is angled, which makes it quite impossible to be penetrated, as picture above shows. higher the impact angle, harder it is to penetrate. Under that angled armor is plate, which has no angle. that should be easy to penetrate. But no.
All of the rounds first have to penetrate rear skin at high angle, then perhaps some structures, most of them will hit radios, which "armor" value i dont know or cannot guess. After those there is fuel tank. I dont know that from which material it is made, but it as well, works as protection for pilot, much more so, if it is full of fuel, (which is rare thing to be)
it might be quite hard if impossible to kill pilot directly from behind. i dont know, but some gun vids gives impression that it is so. targeted 109s keep maneuvering after fuselage is hit from behind or nearly behind at place where pilot would be. from side, it is totally possible. In this case actually, Cannon HE shell might be more effective in wounding or perhaps killing the pilot, if its shot from behind or nearly behind, hitting side of the cocpit, which then gives fragments free path to pilot. Pilot would die if frag would hit him at spine, brains or hearth, instantly. well, spine would just paralyze him. Anyway, there is in my earlier post that Spitfire pilot, who received 3 hits from MG FF cannon behind his cockpit, and he was wounded in legs because of that :o which i wonder how it was possible. Or was he hit with light machineguns as well, which caused it? dunno, also i dont know what kind of pilot armor that spit had in times of BoB.
Control surfaces are harder to destroy with AP ammo, as it demands huge amount of bullets, or hit at hinge of it, which attach it to main frame/wing.
Or it demands that control wires are hit and cut, or parts are bent/deformed which are linked to that wire, making it loose, and if that happens, stick movements doesnt anymore transfer via wires to control surfaces so much, it would make hard maneuvers that way impossible. But this also applies with cannons as well.
against engine AP ammo also have bigger change to effect, again because of their penetration capability. they can enter fuselage at cockpit area, and still go at engine compartment thru firewall/instrument panel. HE ammo would stop at cockpit area from most parts, and fuse isnt having the same power as higher cal AP has.
in that kind of areas AP rounds shines against HE ammo. Much better. they arent in that case, comparable, as they arent in structural damage as well.
HE ammo also cannot travel trough wing from behind and hit ammo box at frontal part of it, but AP ammo can. It can ignite gunpowder from them, or even detonate its ammo. Minengeshoss ammo is the easiest to detonate, because of their thin walls compared to normal HE ammo. PETN is also sensitive to detonate from such hit. Also if the fuse of it is hit, its quaranteed detonation or explosives. That creates really big explosion what is seen when FW190s are hit on wing. Explosion is white because gun powder also goes off, though, its likely, that PETN or Incendiary ammo creates white puffs as well, as is seen in german guncams. some hits from german make black puffs from explosions, but some are white. i know TNT makes black cloud. i think ANFO also makes black, as this video indicates. (first thing coming up from ground is black explosion gas with smoke in it, after that follows more heavy dust of earth, then bigger pieces, all in order of mass. lightest things accelerate fastest.
Tho this has nothing to do again with issue :P
Like i have said, the effectivenes of them is based differently in reality. the way they work are completelly different. They are invented to work differently. Their purpose is to work differently.
Its like using Fragment shells against tanks. (every early tank was vulnerable to 75mm-76mm cal HE shell actually, and i believe Russian T-111(T-46-5) was first tank to be able to survive 75mm HE shells. front armor was 60mm thick. this at least according one book i got..
anyway, my conclusion is:
it takes alot more hits from AP rounds to produce as much structural or skin area damage to aircraft than it takes cannon HE ammo.
it takes more HE rounds to burrow inside aircraf trough all to layers/equipment to reach penetration depth which AP rounds posses.
AP is able to reach parts from angle which HE ammo cant. But, also there is that If you hit engine cowling with AP but it doesnt hit engine or its pipes/electric wires etc, it just goes off, wihtout doing much, and wiht HE ammo, detonating on skin next to engine, would do damage to those parts.
Both of the ammo types have advantages and disadvantages.
But if i would have to choose, i would take cannon because of its destructive power.
and This is what every country have chosen. Every one of them is using High explosive rounds in their cannons. I dont even know, if there is AP ammo at all for them, except for tank buster cannon, like GAU-8, with its depleted uranium rounds. (this gun was designed for anti tank role from the start, not for Air to Air battle.)
Attack Choppa Apache has Dual Purpose rounds, which have fragmentation body, and really small hollow charge in nose of it. Round is filled with 28 g of explosives(behind copper cone of course) it cannot penetrate MBT:s with that small HEAT, but light armored vehicles it can. I dont penetration value of that HEAT on it, but it cannot be much, but i believe its more than what that cannon could do with AP rounds. otherwise it would shoot AP-HE belt? Though, DP ammo makes both of that with same ammo :P And, muzzle velocity on that cannon isnt too big, or accuracy, according vids. (you can calculate how far they shoot approximately, if you know muzzle velocity. Though it drops fast because it is partly empty(hollow charge cone) plus it has light material in it (HE stuff).
Here is picture of that 109 for everyone to imagine bullet penetration paths through different parts and angles, as well to imagine what would HE rounds do at same area of hit compared to AP hit, from same direction.
heres P-47 pic also for you to think about how ammo would work in different places on it.
Edited by Stafroty, 25 June 2014 - 10:09 PM.